package br.org.ifrr.security;

/*
 * Copyright 2004-2012 ICEsoft Technologies Canada Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an "AS
 * IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.security.web.RedirectStrategy;
import org.springframework.security.web.util.UrlUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * This class extends the default redirect strategy provided by Spring Security
 * 3.1m2
 * 
 * @author Ben Simpson <ben.simpson@icesoft.com.com> Date: 2/9/11 Time: 2:51 PM
 */
public class JsfRedirectStrategy implements RedirectStrategy {

	protected final Log logger = LogFactory.getLog(getClass());

	private boolean contextRelative;

	/**
	 * Redirects the response to the supplied URL.
	 * <p>
	 * If <tt>contextRelative</tt> is set, the redirect value will be the value
	 * after the request context path. Note that this will result in the loss of
	 * protocol information (HTTP or HTTPS), so will cause problems if a
	 * redirect is being performed to change to HTTPS, for example.
	 */
	public void sendRedirect(HttpServletRequest request,
			HttpServletResponse response, String url) throws IOException {
		String redirectUrl = calculateRedirectUrl(request.getContextPath(), url);
		redirectUrl = response.encodeRedirectURL(redirectUrl);

		if (logger.isDebugEnabled()) {
			logger.debug("Redirecting to '" + redirectUrl + "'");
		}

		// we should redirect using ajax response if the case warrants
		boolean ajaxRedirect = request.getHeader("faces-request") != null
				&& request.getHeader("faces-request").toLowerCase()
						.indexOf("ajax") > -1;

		if (ajaxRedirect) {
			// javax.faces.context.FacesContext ctxt =
			// javax.faces.context.FacesContext.getCurrentInstance();
			// ctxt.getExternalContext().redirect(redirectUrl);

			String ajaxRedirectXml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
					+ "<partial-response><redirect url=\""
					+ redirectUrl
					+ "\"></redirect></partial-response>";
			response.setContentType("text/xml");
			response.getWriter().write(ajaxRedirectXml);
		} else {
			response.sendRedirect(redirectUrl);
		}

	}

	private String calculateRedirectUrl(String contextPath, String url) {
		if (!UrlUtils.isAbsoluteUrl(url)) {
			if (contextRelative) {
				return url;
			} else {
				return contextPath + url;
			}
		}

		// Full URL, including http(s)://

		if (!contextRelative) {
			return url;
		}

		// Calculate the relative URL from the fully qualified URL, minus the
		// scheme and base context.
		url = url.substring(url.indexOf("://") + 3); // strip off scheme
		url = url.substring(url.indexOf(contextPath) + contextPath.length());

		if (url.length() > 1 && url.charAt(0) == '/') {
			url = url.substring(1);
		}

		return url;
	}

	/**
	 * If <tt>true</tt>, causes any redirection URLs to be calculated minus the
	 * protocol and context path (defaults to <tt>false</tt>).
	 */
	public void setContextRelative(boolean useRelativeContext) {
		this.contextRelative = useRelativeContext;
	}
}
